People in the Eastern Hemisphere may see Earth’s shadow pass over the lunar surface, covering our world’s natural satellite in a flush of red.

Lunar eclipses only ever happen during the full Moon, when the Sun and Moon are on opposite sides of the Earth. When things line up just right, the Earth’s shadow falls on the near side of the Moon, blocking almost all of the Sun’s light from reaching the lunar surface.

The full moon on Sept. 7, 2025 will be a "blood moon" total lunar eclipse. Here's who will see the longest total lunar eclipse since 2022.